An experimental and numerical study has been carried out to investigate the heat transfer by natural convection and radiation in a two dimensional annulus enclosure filled with porous media (glass beads) between two horizontal concentric cylinders. The outer cylinders are of (100, 82 and70mm) outside diameters and the inner cylinder of 27 mm outside diameter with (or without) annular fins attached to it. Under steady state condition; the inner cylinder surface is maintained at a high temperature by applying a uniform heat flux and the outer cylinder surface at a low temperature inside a freezer. The experiments were carried out for an annulus filled with
glass beads at a range of modified Rayleigh number (4.9 ≤ Ra≤ 69), radiation parameter (0<Rd<10), with fin length of (Hf=3, 7 and 11mm), with radius ratios of (Rr=(r1/r2) =0.1405,0.2045, 0.293 and 0.3649 ), number of fins (n=0, 12, 23 and 45). Finite difference method with Boussinesq's approximation is used to solve the continuity, energy and momentum equations.
The numerical solution is capable of calculating the streamline, the temperature field, the velocity field, the local and average Nusselt number. A computer program in Mat lab has been built to carry out the numerical solution. The numerical study was done for a range of modified Rayleigh number (4.9 ≤ Ra ≤ 300). Results show that the average Nusselt number is nearly constant for Ra less than 100 and increased with an increase in modified Rayleigh number.
Nusselt number hardly affected by glass beads size and insignificant affected by Rd for Ra less than 100. Decreasing Rr cause clearly increase in average Nusselt number and increasing fin length or fin number decrease heat transfer.
The need for a flexible and cost effective biometric security system is the inspired of this paper. Face recognition is a good contactless biometric and it is suitable and applicable for Wireless Sensor Network (WSN). Image processing and image communication is a challenges task in WSN due to the heavy processing and communication that reduce the life time of the network. This paper proposed a face recognition algorithm on WSN depending on the principles of the unique algorithm that hold the capacity of the network to the sink node and compress the communication data to 89.5%. An efficient hybrid method is introduced based upon the advantage of Zak transform to offprint the farthest different features of the face and Eigen face method to
... Show MoreBackground: The rhizome of ginger is used in cooking and for medicinal purposes such as anti-bacterial, anti-fungal, anti-inflammatory and antioxidant. The aims of the study were to test the effect of ethanolic extract of ginger on growth, adherence and acidogenicity of mutans streptococci in comparison to chlorhexidine gluconate 0.2% and de-ionized water. Materials and methods: From saliva often volunteers (dental students 20-22 years); mutans streptococci was isolated, purified and diagnosed according to morphological characteristic and biochemical tests. Ginger was powdered and extracted, different concentrations of ginger extract were prepared. Chlorhexidine gluconate 0.2% used as a control positive; while de-ionized water was used as a
... Show MoreIn this work, watershed transform method was implemented to detect and extract tumors and abnormalities in MRI brain skull stripped images. An adaptive technique has been proposed to improve the performance of this method.Watershed transform algorithm based on clustering techniques: K-Means and FCM were implemented to reduce the oversegmentation problem. The K-Means and FCM clustered images were utilized as input images to the watershed algorithm as well as of the original image. The relative surface area of the extracted tumor region was calculated for each application. The results showed that watershed trnsform algorithm succeedeed to detect and extract the brain tumor regions very well according to the consult of a specialist doctor a
... Show MoreIn any security system, we need a high level of security, to maintain the secrecy of important data. Steganography is one of the security systems that are hiding secret information within a certain cover (video, image, sound, text), so that the adversary does not suspect the existence of such confidential information. In our proposed work will hide secret messages (Arabic or English) text in the Arabic cover text, we employed the RNA as a tool for encoding the secret information and used non-printed characters to hide these codes. Each character (English or Arabic) is represented by using only six bits based on secret tables this operation has provided a good compression since each Arabic character needs 16 bits and each English characte
... Show MoreThe Present study was aimed to evaluate the responses of sixteen species of barley Hordeum vulgar L. cultivated in Iraq against drought stress through treatments of seedling with varying concentrations of Polyethylene glycol (PEG6000) to reach the water stress(-3,-6,-9) in addition to control (without PEG 6000). The results showed variation of barley species in their ability to tolerate the drought stress. For instance, Boraq and Arefat were shown to be the most tolerable species, since their percentage of seeds germination were non significantly affected by the highest water potential (-9) bar, while (bawadi,amal,nor alqadsea and nomar) were shown to be moderately drought tolerable, since their percentage of seeds germ
... Show MoreBackground: The Aim Of This Study Is To Determine The Modalities Of Treatment Of GTD In Baghdad Teaching Hospital And To Assess The Efficacy Of Our Management Protocols.
Patients &Methods: Department Of Obstetrics & Gynecology- Baghdad Teaching Hospital. Retrospective Analysis Of Case Records Between January 1999 To December2000. 41 Patients' Data Were Reviewed For Age, Gravidity, Parity, Blood Group, Antecedent Pregnancy And Clinical Presentation At The Time Of Diagnosis. Monitoring Of Hcg Level Before And After Chemotherapy, Other Investigations Were Reviewed, Looking For Number, Size And Site Of Metastasis. The Patient Were Classified According To WHO Scoring System. We Evaluate The Lines )f Ma
The purpose of this research was to examine the impact of varying doses of ginger powder on broiler productivity. There were 180 commercial strain Ross 308 day old chicks utilized in the experiment, and each chick was weighed and allocated randomly among four treatments. Three different treatments were tested, each with a replication of 15 chicks. The diet was supplemented with 0.5, 1.0 and 2.0g/kg of ginger powder, respectively, as a control. As compared to the other treatments, the control group had considerably higher body weights, weight growth, feed intake, and feed conversion ratio. Ginger powder use was shown to have a detrimental impact on growth in this investigation.
Thirty pregnant albino mice with average body weight of 25-30gm and 8-14 weeks old were used to investigate the toxicity of the oral administration of anticancer methotrexate on kidneys after birth. Pregnant were received (single dose) of drug at different days of gestation and were divided into three groups (10mice / group), control groups were administered distilled water, the two remaining groups were administered by 2.5 and 7.5 mg/kg body weight of methotrexate. The changes in kidneys of newborns revealed significant (p<0.05) decrease in kidneys weights, kidneys lengths, pelvises lengths, and glomeruli diameters. The increase in concentration of methotrexate has increasing significant effect on kidneys of embryo and newborns.
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The research aims to measure the accounting conservatism practice of listed companies in the Iraq stock exchange using Basu model to measure the degree of accounting conservatism in a sample of companies of (21) companies for the period from 2007 to 2011, the researcher found that most of the listed companies in the market exercised accounting conservatism when measurement and disclosure of the result of the activity and financial position and there is a variation in the degree of accounting conservatism between economic sectors , which included banking , investment , insurance , industry , agriculture , tourism and hotels.
Because the practice of accounting conservatism properly
... Show MoreThe purpose of this paper is to study a new class of fuzzy covering dimension functions, called fuzzy